Magnesium oxide is classified into two types: light and heavy. Light magnesium oxide is a loose, white, amorphous powder that is odorless, tasteless, and non-toxic, with a density of 3.58 g/cm³. It is sparingly soluble in pure water and organic solvents, though its solubility in water increases in the presence of carbon dioxide; it is soluble in acids and ammonium salt solutions. High-temperature calcination transforms it into a crystalline form, and exposure to atmospheric carbon dioxide causes it to form magnesium carbonate double salts. Heavy magnesium oxide is a dense, white or beige powder. It reacts readily with water and easily absorbs moisture and carbon dioxide when exposed to air; it gels and hardens when mixed with magnesium chloride solution.
Driven by industrial upgrading and the growing demand for high-tech functional materials, a series of advanced, fine magnesium oxide products has been developed. These comprise nearly ten varieties, including grades for premium lubricants, high-end leather tanning (alkali-boosting), food applications, pharmaceuticals, silicon steel, premium electromagnetic applications, and high-purity magnesium oxide.